Re: 0.0.3d-e: JFS: Unrecognised features on journal

From: Andreas Dilger <adilger turbolinux com>

To: ext3-users redhat com

Subject: Re: 0.0.3d-e: JFS: Unrecognised features on journal

Date: Wed, 24 Jan 2001 10:54:11 -0700 (MST)

Brian Murrell writes:
> I updated my kernel from 0.0.3d to 0.0.3e using the "d-e" patch in the
> 0.0.3e tarball.
I presume you mean ext3-0.0.5e?
> When I try to boot the new kernel on a machine with
> an ext3 root filesystem I am getting the message:
>
> JFS: Unrecognised features on journal
>
> Does this sound feasible or even somewhat expected? Is there any
> interest in me doing some debugging of this?
This is expected, given the problems that you previously had. It was
a bug in the older ext3 code that is now detected by the new code.
> Is there any way to deal with this without having to boot the new
> kernel with ext2 and recreating the journal?
I think you can fix it by using these options when you first mount the fs:
noload,journal=<inum>
where <inum> is the inode number of the existing journal, as told by dumpe2fs.
What this does is tell the kernel not to use the existing journal, and then
by supplying a "new" journal inode number it creates a new journal there.
For root, you need to specify "rootflags=noload,journal=<inum>" at the LILO
prompt.
I just checked, and journal_create() zeroes all of the journal blocks, so
this will fix the "Unrecognised features on journal" error. The problem
was that the old "update journal to v2" code didn't clear the feature
flags, so random junk was there for "features". This has been fixed.
Cheers, Andreas
--
Andreas Dilger \ "If a man ate a pound of pasta and a pound of antipasto,
\ would they cancel out, leaving him still hungry?"
http://www-mddsp.enel.ucalgary.ca/People/adilger/ -- Dogbert